Congress is going to war with the Central Intelligence Agency, spurred by Feinstein's allegation the agency may have broken the law and violated the U.S. Constitution by searching a stand-alone congressional computer network.

Feinstein's scathing comments, which Vermont Democratic Sen. Pat Leahy said were among the most important in Senate floor history, opened up a public chapter in a long simmering dispute.

"The CIA did not ask the committee or its staff if the committee had access to the internal review or how we obtained it," Feinstein said in her blistering remarks. "Instead, the CIA just went and searched the committee's computer."

The CIA provided Congress with the computer network to allow the Senate Intelligence Committee to review classified documents at CIA headquarters as part of an investigation into the CIA's Bush-era detention and interrogation programs. The incident in question occurred in December, when Intelligence Committee investigators got ahold of an internal agency review casting a particularly bad light on the interrogation and detention programs, which were ended by President Barack Obama.

According to Feinstein, CIA officials then searched the computers to try to determine how the congressional investigators gained access to the information, Feinstein. Feinstein emphasized that the committee did nothing improper to gain access to the internal reports.

During an event at the Council on Foreign Relations, CIA Director John Brennan denied the allegations, saying "nothing could be further from the truth." However, numerous Senate power players, including Senate Majority Leader Harry Reid, backed up Feinstein's charges and called for increased scrutiny on the CIA.

"I believe in the separation of powers. I support Sen. Feinstein unequivocally," Reid told reporters in Capitol Hill on Tuesday. "And I'm disappointed that the CIA is apparently unrepentant on what I understand they did."

Other senators from both parties also supported Feinstein's accusations.

"I applaud Chairman Feinstein for setting the record straight today on the Senate floor about the CIA's actions to subvert congressional oversight," said Colorado Sen. Mark Udall, a member of the Senate Intelligence Committee.

Udall went on to say the CIA was "trying to hide the truth from the American people about this program and undermine the Senate Intelligence Committee's oversight role." Oregon Sen. Ron Wyden, another member of the Intelligence Committee, called the CIA's actions an "unprecedented invasion." Sen. Lindsey Graham, a Republican from South Carolina, said Congress should declare "war" if the allegations are true.

Feinstein's criticism is particularly important because she has been one of the staunchest defenders of intelligence agencies. This includes full-throated defenses of the National Security Agency amid detailed revelations of surveillance programs from former NSA contractor Edward Snowden last summer. She called Snowden a traitor for leaking the documents.

"When you've lost Dianne Feinstein," one congressional source told Business Insider, "you're in trouble as an intelligence agency."

Committee staffers have for four years been sifting through the 6,000-plus page CIA report on the Bush-era programs. Part of the report cites information from the document detailing the "Panetta Review," which was named after former CIA Director Leon Panetta. CIA officials said through press reports they did not make the document available to Congress, something Feinstein denied. She pointed to the press reports as the reason for giving her speech.

"Our staff involved in this matter have the appropriate clearances, handled this sensitive material according to established procedures and practice to protect classified information, and were provided access to the Panetta Review by the CIA itself," Feinstein said.

Thus far, the White House has tried to walk a fine line between the two warring factions by offering signals of support for both Feinstein and Brennan. White House press secretary Jay Carney told reporters President Barack Obama has "full confidence" in Brennan, though he also noted the White House supports the declassification of the report.

Some senators, too, were careful not to rush to judgment. Florida Sen. Marco Rubio told Bloomberg there should be an "impartial investigation." Barbara Mikulski, a Democrat from Maryland, simply called for "more facts."